ABSTRACT
This study was conducted to compare three strains (Arbor Acre, Marshal and Ross) of broiler chickens using growth traits, biochemical profile and mathematical models (Gompertz, Logistics and Simple linear regressions) with the view of identifying the best strain and the most suitable model for fitting growth curve in broilers. A total of 225 birds (75 per strain) were used. The traits recorded at 2, 4, 6 and 8 weeks of age were body weight, shank length (SL), thigh length (TL), body length (BL) and breast width (BRW) while the traits recorded at 4 and 8 weeks for biochemical profile were glucose (GLU), urea, creatinine (CRE), albumin (ALB) and total protein (TP). At the end of 8 weeks of age, 27 birds from 3 treatments, (9 birds per treatment) were used for carcass traits analysis. The carcass traits measured were carcass weight (CW), breast weight (BRW), thigh weight (TW), drum stick weight (DS), shank weight (SW), gizzard (GZ) and liver. Statistical analysis was done using General linear model procedure of Statistical Analysis System and Python programming interface. The mean body weights obtained at 2, 4, 6, and 8 weeks of age for Arbor acre, Ross and Marshal were 168.40, 494.52, 1085.14 and 1458.96g, 172.14, 505.40, 1044 and 1377g and 145.64, 401.65, 946.58 and 1272.06g, respectively. SL obtained at 2, 4, 6, and 8 weeks of age for Arbor acre, Ross and Marshal were 6.71, 9.42, 13.15, and 14.59cm, 7.24, 10.34, 13.08, and 14.13cm and 7.07, 9.45, 12.19 and 13.72cm, respectively. BRW obtained at 2, 4, 6, and 8 weeks of age for Arbor acre, Ross and Marshal were 13.12, 16.86, 25.04 and 27.49cm, 13.86, 20.71, 23.68 and 27.10cm, 13.22, 17.81, 23.68 and 25.70cm respectively. Similarly, TL obtained at 2, 4, 6, and 8 weeks of age for Arbor acre, Ross and Marshal were 4.95, 6.33, 9.13 and 9.85cm, 5.00, 6.83, 9.26 and 9.34cm and 4.62, 6.22, 8.38, and 8.52cm, respectively. Lastly, BL obtained at 2, 4, 6, and 8 weeks of age for Arbor acre, Ross and Marshal were 24.17, 32.21, 45.81 and 52.92, 26.16, 35.01, 45.45 and 51.97cm, 24.17, 32.54, 44.67 and 50.27cm, respectively. Effect of strain on blood viii biochemical traits were not significant (P>0.05) between the three strains. Similarly, effect of strain on carcass traits were not significant (P>0.05) except for drumsticks weight (DS) which no significant (P>0.05) effect between Ross and Arbor acre with corresponding values of 161.33Â6.15g and 145.66Â6.15g respectively while Arbor acre and Marshal (140.33Â5.77) also had no significant (P>0.05) effect. Correlation coefficients between body weight (g) and body linear measurement (cm) traits were moderate to highly significant (P<0.01) for all the strains at age 2, 4, 6 and 8 weeks. Blood biochemical traits had low positive to high negative associations with other traits of all the strains at 4 and 8 weeks of age. Carcass weight had positive and highly significant (P<0.01) associations with BRW (0.92), TW (0.84) and DS (0.97) in Arbor acre. Similarly corresponding values of BRW (0.82), TW (0.86) and DS (0.76) were recorded for Ross while BRW (0.94), TW (0.98), DS (0.91) were recorded for Marshal. Ross and Arbor acre used for this study showed a good difference for body weight than Marshal strain. The comparison of growth curves using mathematical models in this study showed that, based on the leading key indicators of low Mean square errors (MSE), high coefficient of determination and high correlation coefficients, simple linear regression (SLR) was more appropriate to describe growth pattern of Arbor acre, Ross and Marshal strains compared to Gompertz (GOM) and Logistics (LOG).
